Control mechanism for honing machines



Jan. 26, 1954 E. Y. SEBORG CONTROL MECHANISM FOR HONING MACHINES 4 Sheets-Sheet 1 Filed Jan. 6. 1950 soL-a N 6 1 ig w? W 6 armed-1: g lflvvompt Jan. 26, 1954 E. Y. SEBORG 2,667,016

.CONTROL MECHANISM FOR HONING MACHINES Filed Jan. 6, 1950 4 Sheets-Sheet 2 OLI E? C-cw-neci: Saba? Jan. 26, 1954 E. Y. SEBORG CONTROL MECHANISM FOR HONING' MACHINES 4 Sheets-Sheet 5 Filed Jan. 6, 1950 Jan. 26, 1954 E. Y. SEBORG CONTROL MECHANISM FOR HONING MACHINES Filed Jan. 6, 1950 4 Sheets-Sheet 4 NVBNTOM vane s bogg Patented Jan. 26, 1 9 54 CONTROL MECHANISM FOR HONING MACHINES Earnest Y. Seborg,

Barnes Drill 00., of Illinois Rockford, Ill., assignor to Rockford, 111., a corporation Application January 6, 1950, Serial N 0. 137,170

Claims.

The invention relates to machines for honing or lapping cylindrical surfaces and more particularly to improved controls for such machines.

In machines of the above general character the tool or hone and the work are carried on separate supports, one of which is mounted for reciprocation relative to the other. The reciprocable support is normally held in a retracted relation when the machine is idle and the tool and work are initially brought into operative association by an advancing movement of that support. Thereafter the support is reciprocated through a plurality of working strokes in which the relative movements of the tool and work are confined range such as to traverse the tool repeatedly from one end of the Work to the other. The abrasive elements of the tool, of course, are adjusted radially into operative engagement with the surface of the work during such reciprocation and the tool may be rotated either continuously or intermittently. When the work is finished to the desired dimensions, the tool is adjusted out of operative engagement with the work and the reciprocatory support is moved through a withdrawal stroke substantially longer than the working stroke to separate the tool and work and return the reciprocatory support to its normal retracted position.

For production use it is customary to provide some type of control means for automatically terminating the working cycle of the machine and for initiating withdrawal of the tool from the work. The control means may be arranged to count the working strokes of the tool or alternatively may comprise a simple timing device or a gauging device arranged for measuring the work. With either of the latter two devices, the cycle terminating action occurs at random with respect to the reciprocation of the tool and work and the withdrawal stroke may be initiated with the tool at any position in the work. When this occurs during an inward or advancing stroke, the portion of the work surface ahead of the tool receives less abrading action than the remainder of the surface and is therefore not finished to precisely the same dimensions, While this difference is very minute, it is nevertheless important in precision finishing operations of the type for which honing and lapping machines are employed.

With the above in view, one object of the invention is to provide improved controls for machines of the above general character which insure precisely uniform finishing of the entire within a predetermined working stroke 2 work surface in each operating cycle of the machine.

Another object is to provide controls whereby a full advancing stroke of the tool is assured betool is withdrawn from the work at the end of each operating cycle and irrespective of the position of the tool at the instant the cycle terminating action takes place.

Still another object is to provide a control system in which the electrical control switches only once in each cycle instead of the tool stroke thereby permitting the use of switches of simple, relatively inexpensive construction.

Other objects and advantages of the invention will become apparent from the following detailed trated in the accompanying drawings, in which: Figure l is a perspective view of a honing machine embodying the features of the invention.

Fig. 2 is a fragmentary front elevational View of a part of the reciprocation controlling mechanism of the machine.

Fig. 3 is a fragmentary view of another part of the control mechanism an upstroke of the tool.

Fig. 4 shows the relative positioning of the control elements on the downstroke of the tool.

Fig. 5 is a diagram of the electrical circuit of the machine shown in Fig. 1.

Fig. 6 is a schematic diagram of the hydraulic circuit of the machine illustrated in Fig. 1, showing the relationship of the operating and control elements of the machine.

Fig. 7 is a schematic diagram of a modified form of the hydraulic circuit.

While the invention bers l2 forming a guideway for a vertically and reciprocated while the workpiece is held.

stationary in the exemplary machine, a, suitable support l8 for the work is provided on the base A motor M (Figs. 1 and mounted on the column In is arranged to'rotatably drive the" spindle l4 through the medium of a splined shaft and suitable gearing 2| (Fig. 6), a part oi; which is enclosed in the upper portion of the column l0 and another part within the head i3. Reciprocation of the spindle to traverse the tool axially of the workis effectedby power-actuated means herein shown as a pressure fluid operated.

actuator including a pair of cylinders 22(Figs. 1 and 6) supported in upright position adjacent the upper end of the column Ill. Each cylinder is fitted with a piston 23 having a downwardly extending piston rod 24 operatively connected with the head l3.

' Pressure fluid for reciprocating the head 13 is suppliedbya pump P (Fig. 6) driven by a motor M-I (Figs. 1 and 5).. In the exemplary machine the pressure fluid operated actuator is of the differential-pressure. type and. accordingly the lower or rod ends of the cylinders. 22 are connected. to receive fluid. under pressure in both the up and down strokes. of the head and the upper ends of the. cylinders are arranged for, connection alternately by a reversing valve RV to the source. of pressure fluid and to a drain. To this end the pump is arranged to draw fluid, such as oil, from a sump or reservoir R and to discharge it under pressure into a main pressure conduit 25. A stop valve SV biased to a position to. by-pass the fluid from the pump back to the" sump R. is arranged to be operated by a solenoid SOL-L to. close. the by-pass at the beginning of an operating cycle, as willappear pres-. ently. The conduit 25 has one branch 26Jextending to'the reversing valve RV and a second branch 21 extending to the lower ends of the cylinders 22. A conventional resistance or foot valve FV interposed in the branch 21 prevents the pistons, from creeping downwardly when the machine is idle.

The reversing valve RV as shown is operated to its alternate positions by pressure fluid under control of a two-position pilot valve PV. As the head l3 reaches the upper end of the work ing stroke, the pilot. valve PV is rocked. from the up position in which it is shown in Fig. 6 to a down position. Pressure fluidfrom the branch 28 oi'-the main pressure conduit is then directed through a conduit 29, a normally open pull-out. or withdrawalvalve WV and a conduit 30 to one endof the housing of the valve RV so as to shift its plunger 3| from the up position shown to its other or down" position. With the valve plunger 3.1 thus positioned, the upper ends of the cylinders 22 are. connected by way of a conduit 32 and branch conduit 26 to the main pressure conduit. 25.

Accordingly, fluid supplied to the upper ends. of the cylinders 22 is effective to shift downwardly against the force exerted by the fluid against the smaller efiective areas at. the

the pistons 23 and head, l3.

- supportedon the column.

chain dispcsedparallel to the reciprocatory path lower ends of the pistons. Fluid is discharged from the lower ends of the cylinders and returned to the main pressure line 25. A metering valve NW of any preferred character may be interposed in the conduit 25 to regulate the rate of movement of the pistons.

Upon, operation of the. pilot. valve PV to its alternate position, pressure fluid from the main conduit 25 is directed by way of a conduit 33 to'the other end of the housing of the reversing valve RV. Thevalve plunger 3| of the reversing valve is then shifted to its alternate or up" position so as to connect conduit 32 with a drain conduit 34 leading. back to the sump R. The piston 23' and'headl3 are therefore moved upwardly untilthe pilot valve is operated at the upper. end of the working stroke or until the head l3 reaches its fully retracted position. This latter movement of the head beyond the working stroke range is initiated by operation of the valve WV which establishes a by-pass to. the drain for both the conduit 29 and the conduit, 30. Valve WV is arranged to be operated by a solenoid SOL-2 at the end of an operating cycle as will be. describedpresently.

In the exemplary machine, the shiitingof the pilot valve PV from one position to the other is efiected by controlmechanism including a shifter rod 35 connected at one end to a pivoted rocker arm 35 cooperating with a control cam 3'5. This control cam. is rotatably mounted on a shaft 38 which has keyed thereon a sprocket wheel 39,. An endless chain 43 running over the sprocket wheel 39and a companion sprocket wheel 4| is IB- with onerun of the of the head l3. This chain run is operatively connectedwith an arm 42 projecting from the head l3 whereby the sprocket wheel 39 and shaft 33 are rocked or oscillated in timed relation to the reciprocation of the head and through an arc corresponding to the range of travel of the head.

Valve shifting movements areimparted to the cam 37 at the upper and lower limtis of the working stroke through the medium of apair of dogs 45 and 46 carried by a disk member rigid with the shaft 38-. The dogs are mountedon the disk in, circumferentially spaced relation and extend radially therefrom for. engagement alternately with, a finger piece. 48. projecting from an arm 49 rigid with the cam. The arrangement is such that. either dog. on engaging the finger piece shifts the'arm. and cam tive to reposition. the pilotvalve and reverse the direction of movement, of the head l3. lhe arm, the cam and. the shifter rod remain in their set. position of course until the head approaches the opposite endof its working stroke, whereupon the shifting again takes place but. in the opposite di rection.

Havingin mind the construction andrelation of the mechanical and hydraulic elements of the control system above explained, the automatic.

machine will be readily understood upon. reference to the control circuit diagram of Fig. 5. In the electrical control system shown the operating elements of the system are supplied with low voltage current through a trans. former TF connectedto a power line L which supplies currentto the motorsMand M-l.

cycling of the It will be appreciated that at the beginning ofa cycle the toolheadi I3 is in theiully retracted position and the pilot valve. PV and reversing valveRV are in the down position. Upon ma.- nipulation. of a cyclestarting control device, in.

through an angle effec this instance a pushbutton actuated switch S (Fig. 5), relays RI, R2 and R3 are energized. Relay RI closes switches Rl-l and Rl-2 to complete a holding circuit for itself, which circuit includes a normally closed manually operable inching switch S-I, a limit switch LS-l and a normally closed manually operable stop switch S2. The limit switch LS-i is open when the head is is in its upper or retracted position and is closed upon movement of the head from that position. Opening and closing of the switch is effected in this instance by means of a dog 50 (Figs. 2 and 6) mounted on and rotatable with the control disk 41.

Relay R2 when energized closes switch contacts R24 to start the pump motor M-| and relay R3 closes switch contacts R3-l to start the spindle motor M. Closure of the switch contacts Rl-2 completes a circuit for energizing a control relay R4 which closes contacts R4-l to energize the solenoid SOL-i and thus interrupt the by-passing of the pump P so that fluid under pressure is supplied to the operating elements of the machine.

After starting the machine in the above manner the head 13 is advanced to associate the tool with the work, such advance continuing until the tool is traversed through the work, at which time the pilot valve PV is actuated in the manner heretofore explained to reverse the direction of movement of the head. The head is accordingly given a return movement which is reversed at the upper end of the working stroke as above explained. Such reciprocation continues within the working range until the cycle is interrupted either by closure of a normally open manually operable cycle stop switch S-3 or by the operation of a cycle stop device SD which may be in the nature of a timer, gauge, or the like. In the particular machine illustrated, the stop device comprises an electrically driven timer started in operation by closure of a limit switch LS-Z coincidentally with of the cam member 31 which has a cam surface at its lower end adapted to hold the switch closed as long as the reciprocation is confined within the working range. Control device SD when energized closes a switch SD-l after a suitable timing cycle.

is delayed until the advancing stroke is completed. This insures uniform tool action over the entire such as the shifter rod 35 to prevent completion of the control circuit prepared by the switches S-3 and SD-i while the head is advancing.

Referring to Figs. 3 and 4, the auxiliary control device 5| in its preferred form comprises a normally open switch S4 (Fig. 5) adapted to be closed by inward movement of an operating member or plunger 52. Switch 3-4 is enclosed in a housing 53 supported on the movable core 54 of a solenoid SOL-3 which when energized shifts bodily from the position shown in full the position shown in broken lines in those figures. A spring 55 acting on the core 54 returns the switch to normal rest position when the solenoid is deenergized.

For operating the switch 8-4, abutment means 55 is provided on the shifter rod for engagement by the switch plunger 52 incident to the shifting of the switch from rest position. The abutment means as herein shown comprises a stop screw adjustably threaded into a bracket 51 rigidly mounted on the shifter rod 35. The arrangement is such that when the shifter rod occupies its the upward stroke of the head, positioned for operative engagement by the plunger 52 upon energization of the solenoid SOL-3 whereby the switch 8-4 is operated to closed position. Conversely, when the shifter rod occupies its right-hand position (see Fig. 4) during the downward or advancing stroke of the head, the abutment 55 is moved beyond the range of the plunger 52. Energization of the solenoid SOL-3 is therefore ineffective to operate or close the switch until the shifter rod is again moved to the left as the head reaches the end of its advancing stroke.

Referring now to Fig. 5 of the drawings, solenoid SOL-3 is energized upon closure of either switch S-3 or swicth S-D-l. When switch 8-4 is closed, a circuit is completed by way of closed switch contacts R4-2 of control relay R4 for energizing control relay R5. This relay upon energization completes a holding circuit for itself by closing switch contacts R54 and additionally completes a holding circuit for solenoid SOL-3 by closing contacts R5-2. By closing contacts R5 3 relay R5 completes a circuit for solenoid SOL-2, which as previously explained, shifts the with drawal valve WV to its alternate position so as to prevent operation of the reversing valve RV as the head reaches the upper end of its working stroke. Consequently, movement of the head continues until the head reaches retracted position whereupon limit switch LS-l is opened by control dog 50.

Opening of limit switch LS-i results in the deenergization of all of the control relays and the various solenoids. Solenoid SOL| permits stop valve SV to open and by-pass the fluid from the pump P. Relay R2 stops the pump motor M-l and relay R3 opens the running circuit for the motor M. -To provide for quickly stopping this motor, a conventional plugging switch PS is provided which is closed when the motor is running in the normal forward direction. When this switch is closed, the deenergization of relay R3 and closure of switch contacts R3-2 complete a circuit for a reversing relay RE which closes switch contacts R6-! to reverse the motor M. Such reversal brings the motor to a quick stop and the concurrent opening of the plugging switch brings about the immediate deenergization of the relay R6 and consequent interruption of the reversing circuit. Relay R6 when energized also opens switch contacts R6-2 to prevent accidental energization of relay R3 before the motor M is brought to a complete stop.

The application of the improved full stroke control arrangement to a honing machine equipped.with'pressurerfluid-operated headrecip rocating means of the double-acting type' is; shown in Fig. '7 of the drawings. the pressure fluid actuated means includes a cylinder fifl'with a-working pistonfi'l operatively connected with the head l3" by a piston rodlfiz.

The upper and lower endsof the cylinder 60 are:

connected'respectivelywith a reversing valve RV by conduits 63 and 64. Reversing valve RV is shiftable betweentwo positions a .pilot valve PV which in turn is shifted in synchronism withthe movements of the head by control mechanism similar to that heretofore:de--

scribed, including the shifter rod ;v

In the-normal operation of themachine the: plunger of the pilot valve PV" is positioned. as head moves upwardly dur. When'the dog l engages shown in Fig. 7 as the ing a working stroke. the. finger 48, the .valve PV is shifted to the right. Pressure fluid from a pump P isthereupon directed by way of aconduit 65, branchconduitfit, withdrawal valve conduit 61, pilot valve PV and conduit 68 tothe housing of the reversing valve'to shift the plunger of'that valveto the down position.

the lower end of the cylinder by way of the conduit 59, reversing valve and conduit 64 while fluid is exhausted from the. upper. endof the cylinder by way of'conduit 63, reversing'valve, conduit 13, pilot valve and drain I I.

When the tool is, to be withdrawn from the work at the end of an operating cycle, the with:-

drawal valve WV is operated by'energization of when the pilot valve PV is reversed at the upper end of: the' working stroke no corresponding reversal ofthe its solenoid SOL-2. Consequently,

valve RV occurs since the pressureconduit 61 is closed by the withdrawal valve. movement of the head therefore continuesuntil the head reaches its'fully retracted. positiontand the ma-chineis stopped nism, as explained heretofore.

In each shift of the pilot valve PV which is timed relation tothev efiected mechanically in movements of the head as heretofore described,

the exhaust for-the cylinder 60 through either of conduits-H1 or 13 and the pilot valve is-closed. immediately, thus instantaneously interrupting the movement of the head irrespective of any con valve. This p'er trolling action by the reversing mits of'very accurate determination of the limit position of the working stroke regardless of any' lag in the response of the reversing valve. When the withdrawal'valve is operated, a new exhaust circuit is provided for the actuator cylinder by a by-pass valve BV operated through the di version of pressure fluid theretobyway'of con-. duit 14.

In the modified form of the machine, the auxe iliary controlling device 5| is associated with. the shifter rod 35 in precisely the same manner asin the previously described machine. Furthermore,

In this case under control of- The valve accordingly. isset. to. direct pressure fluid byway of .the conduit 65 fluid The upward by the control mechaeseemsits action. ini delaying: energization of; the. withedrawal'solenoid SOL-Zis thesame.

ltwill b'e apparent fromithe' foregoing that'the invention provides improved controls for honingi machines whereby a full stroke of the tool is o'o'' tained' at the end of each cycle regardless of the honing i ofthe withdrawal: initiating action with reference to= the reciprocation of the toolhead Uniformfinishing of the entire area of the work piece. is therefore insured. The mechanismlfor effecting suchicontrol is vefiicient and dependable.

Since it utilizes switch means operable only once:

in each cycle, the switch means may be of relae tively simple and inexpensive construction;

I' claim asmy invention: 1. Ina honing machine support, in. combination,

said working range to a retracted position, control mechanism operatively connected with said power actuated'means includinga control mamber shiftable alternately betweentwopositions:

as the support approaches opposite ends of: its working range, abutment means mounted on and shiftable with said control member, av control:

switch mounted forbodily movement toward and flOlll said abutment means and normally re? tained in a posztionremotefrom said abutment means, means opcrableto shift said control switch towardsaid abutment means and into a posi tion' to be actuated thereby when. the control member occupies one of its twopositions, and'a' control device operableresponsive to the actuae tion of. said control switch for initiating move-- ment of the support to-retractedposition 2. In a honing machine having a reciprocatorysupport,.in combination, a main pressure fluid operated actuator operable to reciprocate the support, a source of pressurefluid, a reversing valve connected between said source andlsaid actuator operative to control the supply of press sure-fluid to and-exhaust of spent pressurerfluid' from saidactuator, a pair of pressure fluid operated'actuatorsoperatively associated with said reversing valve ternate positions, a pilot valve connected to control .the supply of pressure fluid'to said valve actuators'and the exhaust'of fluid from aidimain actuator, mechanism in timed relation't'o. the reciprocation of the head, awithdrawal valve effective when operated to block" delivery of. pressure fluid to and thusprevent operation. of said reversing valve following an operation of said pilot valve whereby of the head to a retracted position,,and-a by-pass valve rcsponsiveto the.

to. initiate movement mechanism controlling-the operation of said ac-- withdrawn tuatorto advance the support from a position. intoa predetermined honing. range andthenv toreciprocate the support back and forthbetween limit forward and retracted positions within .said range, a movable member, a. motion transmitting connection betweensaid memher and said power actuatorto move said mem-- ber along a predetermined. path and dispose the member in spaced first and second positions when.

having a reciprocable power-actuated meansoperable to reciprocate said support through" a workingrange andto shift. the support beyond:

for shifting the valve between al-' for operating said pilot valve-- machine, the combination of,

said support is at opposite limits of the forward and return strokes respectively, a second member normally maintained out of said path but movable into the path to a position for engagement by said first member when the latter is in said first position only, means operable at random and while said support is in different positions in different honing cycles to move said second member to said engaging position, and means responsive to the engagement between said two members to modify the action of said controlling mechanism and return stroke of said actuator to be continued beyond the retracted position of said support and thereby return the support to said withdrawn position.

4. In a honing machine, the combination of, a support movable to bring a honing tool into a work bore to be honed, a power actuator for reciprocating said support to hone said bore, mechanism controlling the operation of said actuator to advance the support from a withdrawn position into a predetermined honing range and then to reciprocate the support back and forth between limit forward and retracted positions within said range, a movable element, a first control member mounted on said element for bodily movement therewith, a motion transmitting connection between said element and said power actuator to move said member along a predetermined path and dispose the member in spaced first and second positions when said support is at opposite limits of the forward and return strokes respectively, a stationary element, a second control member mounted on said stationary element and normally inoperatively disposed relative to said first member, one of said members being mounted on the corresponding element for shifting relative thereto to dispose said second member in operative relation to said first member when the latter is in said first position only, means operable at random and while said support is in difierent positions in different honing cycles to shift said one member relative to the corresponding element, and means responsive to said two members when operatively related to modify the action of said controlling mechanism and cause the ensuing return stroke of cause the ensuing said actuator to be continued beyond the retracted position of said support and thereby return the support to said withdrawn position.

In a honing machine, the combination of, a support movable to bring a honing tool into a work bore to be honed, a power actuator for reciprocating said support to hone the bore, mechanism controlling the operation of said actuator to advance the support from a withdrawn position into a predetermined honing range and then to reciprocate the support back and forth between limit forward and retracted positions within said range, a control device operable when actuated to modify the action of said mechanism and cause said actuator to move said support beyond said retracted position to said withdrawn position, means energized at random and while said support is in diiferent positions in diiferent honing cycles, a movable member, a motion transmitting connection between said member and said power actuator to move the member back and forth along a predetermined path in response to reciprocation of said support, and a second member disposed alongside said path to be operatively related to said movable member only upon full advance of said support and operable upon energization of said random means and when operatively related to said movable member to actuate said control device thereby to modify the action of said mechanism and cause said support to move beyond said retracted position to said withdrawn position after a complete advancing stroke.

EARNEST Y. SEBORG.

References Cited in the file of this patent UNITED STATES PATENTS 

